Biomedical subjects

M Furusawa

Publications and source records attributed to M Furusawa.

195 records · Page 11Linked to original sources

PubMedDate not supplied

Structure of thymidine kinase gene introduced into mouse Ltk- cells by a new injection method.

Pricking, a new injection method developed by Yamamoto et al. (1981), can be used to introduce DNA into cultured cells with high efficiency. Closed circular plasmid DNA containing the cloned HSV-TK gene (pTK-1) was introduced by this method and the structure of DNA in stable transformants was examined. In most clones, the introduced DNA was integrated into the mouse genome in a tandemly repeated form. The possibility of multiple integration via mouse middle repetitive sequences was also examined using the chimeric plasmid with TK genes and middle repetitive sequences (pMRTK-1). Digestion with restriction enzymes showed that the middle repetitive sequence used in this experiment had no effect on the efficiency of transformation, suggesting that this sequence is unable to mediate homologous recombination with mouse genomes.

Animals↗

PubMedDate not supplied

Applications of microwave scanning ESR microscope: human tooth with metal.

A microwave scanning ESR microscope has been developed to study the distribution of paramagnetic ions or radicals in various materials, especially in minerals. The microwave scanning microscope consists of a cavity with an aperture over which a sample is moved using mechanical stages and computer-controlled stepping motors. The EPR signal intensities at all positions are composed on a CRT display as an image. A new TE111-mode cylindrical cavity system was designed to obtain better sensitivity and resolution. ESR images of gamma-rayed human teeth were obtained to study the effect of secondary electrons from the adjacent metal on the defect formation in a tooth.

Electron Spin Resonance Spectroscopy↗

PubMedDate not supplied

Production of human alpha-interferon in silkworm using a baculovirus vector.

Microorganisms are generally used for mass production of foreign gene products, but multicellular organisms such as plants have been proposed as an economical alternative. The silkworm may be useful in this context as it can be cultured easily and at low cost. We have therefore developed a virus vector to introduce foreign genes, for example, the gene for human alpha-interferon (IFN-alpha), into silkworms. We used the baculovirus Bombyx mori nuclear polyhedrosis virus (BmNPV) which has a large (greater than 100 kilobases, kb) double-stranded circular DNA genome within its rod-shaped capsid. Baculoviruses have been used previously as vectors for expression of beta-interferon and beta-galactosidase in established cell lines. Although BmNPV has not been used previously as an expression vector, it has an advantage over the baculovirus Autographa californica NPV in that it has a narrower host range and will not grow in wild insect pests in the field. In the present study, the polyhedrin gene encoding the major inclusion body protein of BmNPV was identified by hybridization with complementary DNA and cloned in a plasmid. For insertion of foreign genes, we constructed a recombinant plasmid carrying a polylinker linked to the promoter of the polyhedrin gene, and inserted the IFN-alpha gene into this plasmid. The resulting plasmid and the BmNPV genomic DNA were co-transfected into BM-N cells, and stable recombinant viruses isolated by plaque assay on BM-N cells. The recombinant virus replicated in silkworm larvae, which synthesized as much as 5 X 10(7) units (approximately 50 micrograms) of interferon in their haemolymph.

Amino Acid Sequence↗

PubMedDate not supplied

Tissue distribution of cis-diamminedichloroplatinum(II) following intraperitoneal administration to patients with recurrent gastric cancer.

Using atomic absorption spectrophotometry, we determined the concentration of platinum in tissues obtained at autopsy of 4 patients with recurrent gastric cancer. Patients had been given intraperitoneal cis-diamminedichloroplatinum(II) (cisplatin, CDDP). There was no correlation between the concentration of platinum and the dose of CDDP. Platinum was distributed in all organs examined, the highest amount being in the liver. Thus, when CDDP is administered intraperitoneally for treatment of patients with malignant disease, the toxicity to various organs, including the liver and the kidney, needs to be considered.

Adipose Tissue↗

PubMedDate not supplied

Increased uptake and prolonged retention of actinomycin D by concomitant hyperthermia related to cytotoxic enhancement.

We investigated the possible mechanisms of hyperthermic enhancement of actinomycin D (AMD) cytotoxicity in a neoplastic cell line. The hyperthermic enhancement of AMD cytotoxicity depended on both the temperature and the sequence of the administration. The percentage survival of simultaneous treatment of either 42 or 43 degrees C hyperthermia with 5 micrograms/ml AMD was 42% or 2.2%, respectively, and the amount of AMD in the DNA (DNA-bound AMD) of simultaneous hyperthermia at either 42 or 43 degrees C was 16.5 or 27.2 ng/10(6) cells, respectively. The percentage survival of sequential treatment of 5 micrograms/ml AMD following either 42 or 43 degrees C hyperthermia was 55 or 46%, respectively. The amount of DNA-bound AMD of sequential hyperthermia at either 42 or 43 degrees C was 10.8 or 21.7 ng/10(6) cells, respectively. In addition, the percentage survivals of the S-phase and G1-phase cells concomitantly treated with 43 degrees C hyperthermia and 5 micrograms/ml of AMD were 1.4 and 92%, respectively, and the amounts of DNA-bound AMD of these S-phase and G1-phase cells were 28.2 and 1.6 ng/10(6) cells. These findings suggested that an increased amount of AMD in DNA was responsible for the hyperthermic enhancement of AMD cytotoxicity. When the G1-phase cells were treated with 5 micrograms/ml AMD alone, without hyperthermia, the amount of AMD in acid-soluble fraction of the G1-phase cells was quite low (0.3 ng/10(6) cells). However, concomitant hyperthermia treatment with AMD at the G1-phase significantly increased the AMD amount (1.6 ng/10(6) cells at 42 degrees C, and 3.1 ng/10(6) cells at 43 degrees C) up to a level equal to that in asynchronous (1.7 ng/10(6) cells) and S-phase cells (2.1 ng/10(6) cells) simultaneously treated with hyperthermia and AMD. It was suggested that hyperthermia altered the membrane permeability of the G1-phase cells. The increase of the AMD amount in the DNA might thus be the result of higher intracellular drug concentration.

Animals↗

PubMedDate not supplied

Efficacy of indomethacin pretreatment with regional hyperthermia for treating upper abdominal malignancies.

It is important to reduce a systemic stress during regional hyperthermia against upper abdominal malignancies. A 50 mg indomethacin suppository was administered to five patients with intrahepatic tumour 30 min before hyperthermia. Oral temperature only rose to 37.8 degrees C, heart rate increased to just 110/min, and systolic blood pressure only increased to 134 mmHg. Under these conditions, epinephrine and norepinephrine rose to only 0.09 and 0.25 ng/ml, respectively, which were within normal limits. In addition, prostaglandin E2 (PGE2) did not increase at all. However, when these same five patients were not pretreated with indomethacin, parameters monitoring the systemic condition rose profoundly during hyperthermia. Systemic stress during hyperthermia against upper abdominal malignancies was reduced by the indomethacin pretreatment.

Blood Pressure↗

PubMedDate not supplied

In vitro augmentation of natural killer activity of peripheral blood cells from cancer patients by a DNA fraction from Mycobacterium bovis BCG.

Effects of a DNA-rich fraction from Mycobacterium bovis BCG (MY-1) on the natural killer (NK) activity of peripheral blood lymphocytes (PBL) from healthy donors and cancer patients were studied in vitro. The NK activity of PBL was assessed after incubating PBL for 24 hr in the presence or absence of MY-1 or that digested preliminarily with RNase or DNase. One microgram per ml of MY-1 or that digested with RNase augmented the NK activity of PBL from healthy donors. The activity of MY-1 was abolished by the digestion with DNase. Similarly, the NK activity in all of six patients with gastric cancer, 12 patients with colonic cancer, and six patients with uterine cancer was augmented by incubation with MY-1 (1 microgram/ml and 10 micrograms/ml), although the degree of augmentation varied depending upon the origin of PBL.

Colonic Neoplasms↗

PubMedDate not supplied

Dipyridamole augments the antitumor effects of fluorinated pyrimidines.

The antitumor effects of 5-fluorouracil (5-FU) and its analogues when combined with dipyridamole (DP) were investigated using B16 melanoma cells, in vitro and in vivo. First, the enhancement of 5-FU cytotoxicity by DP was examined in vitro. Cell growth was suppressed significantly by combining 5-FU and a nontoxic dose of DP (2.5 micrograms/ml) as compared to 5-FU alone. Next, the effect of DP was examined in vivo in combination with 5-FU, tegafur (FT) and UFT. UFT had the most remarkable antitumor effect when given in a single equimolar dose. Although DP alone did not affect tumor growth, the growth inhibition by antitumor drugs was augmented by DP. DP enhanced the antitumor effect of UFT significantly (P less than 0.05), and combination treatment with UFT and DP proved to be the most effective regimen for inhibiting growth of B16 melanoma. Combination treatment with UFT and DP shows promise for clinical cancer.

Animals↗

PubMedDate not supplied

Difference in cytotoxicity of paclitaxel against neoplastic and normal cells.

The difference in growth response between neoplastic and contact-sensitive normal cells was investigated by cell growth curve, colony forming efficiency and flow cytometric analysis. Neoplastic cells (MKN-28, MKN-45, and MCF-7), treated with paclitaxel at a concentration of 0.01 mM, showed growth inhibition, low colony-forming efficiency and a prolonged G2+M phase accumulation. Normal cells (Balb/c 3T3 cells and human fibroblasts originating from stomach cancer tissue), treated with paclitaxel at a concentration of less than 0.5 microM, showed no growth inhibition and no decrease in colony-forming efficiency. Normal cells treated with 1 microM of paclitaxel showed low accumulation in G2+M phases. The results show that paclitaxel at concentrations ranging from 0.01 to 0.5 microM had a cytotoxic effect against neoplastic cells but not against normal cells, such as fibroblasts around the cancer cells.

3T3 Cells↗

PubMedDate not supplied

Cytotoxicity of CPT-11 and SN-38 for gastrointestinal and recurrent carcinomas cultured on contact-sensitive plates.

CPT-11 is a derivative of camptothecin, a topoisomerase-I inhibitor with marked cytotoxic activity. We examined the cytotoxicity of CPT-11 and its metabolite SN-38 for primary gastrointestinal carcinoma and various recurrent carcinomas which were cultured on contact-sensitive plates (CSPs). The response rate of seven gastrointestinal carcinomas for either CPT-11 or SN-38 was 71% (5/7). The response was higher than those for other anticancer agents, including adriamycin (ADM), cisplatinum (CDDP) and 5-fluorouracil (5-FU). The mean percent survival of these tumor cells was 69% when incubated with 25 ng/ml of SN-38, which was the lowest survival for all the anticancer drugs tested. IN the case of recurrent carcinomas, the response rate to either CPT-11 or SN-38 was 60% (3/5), and was higher than the rates for MMC, CDDP or 5-FU. The mean percent survival of the recurrent carcinoma cells was 76% in the presence of 25 ng/ml SN-38, and this was once again the lowest survival rate. CPT-11 had a stronger inhibitory effect against one carcinoma than SN-38 when a clinical drug concentration was added to the culture medium, suggesting that CPT-11 itself was cytotoxic. IN addition, one carcinoma with a low response to CDDP also showed no response to CPT-11, but was very occurred because of decreased conversion of CPT-11 to SN-38. Our results suggest that CPT-11 may be a useful agent for the treatment of both primary gastrointestinal cancer and various recurrent carcinomas.

3T3 Cells↗

PubMedDate not supplied

Increased cytotoxicity of 5'-deoxy-5-fluorouridine by prolonged culture with folinic acid.

We investigated the cytotoxic potentiation by folinic acid (FA) of two fluoropyrimidines, 5-fluorouracil (FUra) and 5'-deoxy-5-fluorouracil (5'-dFUrd), against two human neoplastic cell lines (HeLa and KSE-2 cells). The concentrations of fluoropyrimidine (2-10 microM) and FA (1 microM) in media were based on clinically achievable levels, and the duration of culture was relatively long (6 days). The cytotoxic activity of fluorouridine and FA was evaluated by both clonogenic efficiency and thymidylate synthase (TS) inhibition rate of the cells. After combined treatment with 2 microM 5'-dFUrd and 1 microM FA the clonogenic efficiencies of the two cell lines were significantly lower than those after treatment with 5'-dFUrd alone (p < 0.01). Moreover, the TS inhibition rates of these two human cell lines after combined treatment with 10 microM 5'-dFUrd and 1 microM FA were significantly higher than those after treatment with 5'-dFUrd alone (p < 0.01). However, when these two cell lines were exposed to FUra, concomitant treatment with FA did not enhance cytotoxicity. These differences in the cytotoxic properties of FUra and 5'-dFUrd in response to the addition of FA ascribed to the fact that during 2-3 days and 5-6 days after treatment, intracellular concentrations of 5'-dFUrd produced by combined treatment with 10 microM 5'-dFUrd and 1 microM FA were higher than those associated with 10 microM 5'-dFUrd achieved by combined treatment with 5'-dFUrd and FA was also higher than that of FUra during combined treatment with FUra plus FA and that of 5'-dFUrd during treatment with 5'-dFUrd alone. There was no statistically significant difference in intracellular FUra concentrations between combined treatment with FUra plus FA and treatment with FUra alone. Prolonged treatment with 5'-dFUrd and FA in clinically feasible concentrations was thus more effective than the combination of FUra and FA in two human neoplastic cell lines.

Cell Line↗

PubMedDate not supplied

MR imaging of lingual carcinoma: comparison with surgical staging.

The purpose of this study was to determine the usefulness of magnetic resonance (MR) imaging for the preoperative staging of 18 patients with lingual carcinomas. Tumor stage as determined by MR imaging was compared with pathological stage. Conspicuity of tumors was compared among dynamic MR, T2-weighted, and postcontrast T1-weighted images. The tumor stage was evaluated correctly with MR imaging in 15/18 patients (83.3%). One patient was overstaged and two understaged due to incorrect diagnosis of size. In all T4 cases, tumor extension was diagnosed correctly. Dynamic MR and T2-weighted images were superior to postcontrast T1-weighted images in delineating and showing the extension of carcinomas. However, dynamic MR imaging showed no significant superiority to T2-weighted imaging. We conclude that MR imaging is of great value in the staging of lingual carcinoma. Dynamic study should be performed only when the lesion is undetectable or equivocal on T2-weighted imaging.

Adult↗

PubMedDate not supplied

Azelastine: its clinical application for radiation dermatitis.

A retrospective analysis was performed to investigate the radioprotective effects of azelastine against radiation dermatitis for patients with head and neck cancers. The effects of azelastine were studied in 19 patients with laryngeal cancers treated by irradiation. As controls, 29 patients with laryngeal cancers treated by irradiation without the administration of azelastine were studied. All patients were irradiated using 3 MV linac X-rays. Azelastine was administered orally twice a day. Moist desquamation was observed in four of 29 control patients whereas no such moist desquamation developed after the administration of azelastine. Two cases of moist desquamation that developed before the administration of azelastine regressed during irradiation in patients placed on azelastine. Radiotherapy was completed without interruption in all patients treated with azelastine. No severe side effects were observed. Azelastine, administered orally, was a safe drug and has the potential of improving skin tolerance in irradiation therapy.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMedDate not supplied

Carbon-13 magnetic resonance spectroscopy of glucose metabolism in SCC-VII tumors.

We used 13C MR spectroscopy to follow the metabolism of [1-13C]glucose in SCC-VII tumors of C3H/HeN mice. Six different SCC-VII tumors and six muscles of normal legs were used. Spectroscopy was carried out with the intraperitoneal injection of 100 mg of [1-13C]glucose. Six distinct resonances were detected: the alpha and beta anomers of the C1 of glucose, C2,3,4 of glutamate and glutamine, and the C3 of lactate. Signals from [1-13C]glucose were first detected in the spectra of tumor 10 minutes after injection. Signals decreased faster in the SCC-VII tumors than the muscle of normal leg. The presence of 13C of glutamate/glutamine suggested the entry of pyruvate into the TCA cycle in SCC-VII tumor. The more rapid decrease of signals from [1-13C]glucose in the SCC-VII tumor may be attributed to the effects of blood flow volume and metabolic activity.

Animals↗

PubMedDate not supplied

Determination of the optimal pulses in MR imaging with magnetization transfer contrast at 7 Tesla.

OBJECTIVE: The magnetization transfer contrast (MTC) effect depends on the shape, duration, amplitude, and offset frequency of the saturation pulse. In the present study, we investigated optimal combinations of these four parameters in vitro. METHODS: All experiments were performed with a 7.05 Tesla MR system, and the spin echo technique (TR 500/TE 30) was adopted. We used a simple phantom composed of 1% agar and water, representing restricted and free proton pools, respectively. Signal intensity changes were measured in the agar (Ma) and water (Mw), when the shape, duration, magnitude, and offset frequency of the saturation pulses were varied. The MTC effect was examined with the Mw/Ma ratio. RESULTS: The suppression of Mw was less with the gauss pulse than with the square and sinc pulses. The gauss pulse had the best MTC effect. The suppression of both Ma and Mw was greatest with a saturating duration of 60 msec. The MTC effect was greatest with a longer saturation pulse. The larger the amplitude, the stronger the MTC effect obtained. Mw was suppressed with an offset frequency of less than 3 kHz, and the MTC effect was greatest with an offset frequency closer to the spectrum of the free proton pool. CONCLUSION: In the present study the optimal MTC pulse at 7 Tesla is the gauss pulse with longer duration, maximal amplitude, and approximately 3 kHz off resonance.

Contrast Media↗